Improv Quarter Circle Tutorial

Today I want to share the process I used to create the improv quarter circle blocks that I created in the It Comes in Waves quilt. A few things to note before getting started:

I am demonstrating this using the same size blocks (5-inch charm squares) that I used to create the mini quilt. If you are new to sewing curves, I recommend starting with larger blocks / curves as they are more gentle and easier to sew. For instance, try this using 2 layer cake (10-inch square blocks) if you have never sewn a curve before.

This method uses two squares of fabric and creates two improv quarter circle blocks that are inverse images of one another. In other words, one block has Fabric 1 as the quarter circle and Fabric 2 as the arch and the second block has Fabric 2 as the quarter circle and Fabric 1 as the arch.

The tutorial format is photograph followed by descriptive text.

Let’s get started!

Step 1

The first step is to simply collect materials. You will need:

(2) fabric squares that are the same size,

your rotary cutter,

I suggest using a wooden seam roller but you can just use your fingers or other tool (see steps 4 and 5),

pins,

your sewing machine (not pictured), and

an iron (not pictured).

Step 2

Place your two fabrics on top of one another with both fabrics having the right sides facing up. Using your rotary cutter, make a free hand cut of an arc.

This is the scariest part of improv and can be the point that many people stop. If cutting free hand is not something you are comfortable with, consider warming up to taking this leap by using one of these techniques:

Trace an arc using a fabric safe marking device and then use your rotary cutter to cut along the line you marked.

Pin the two fabric squares together around the edges and use scissors to cut an arc.

Combine the two methods above and cut your traced arc using scissors after securing the two pieces of fabric together using pins (to keep the fabric from shifting and roughly aligned).

Step 3

Create your two pairs of blocks by alternating the fabrics for the quarter circle and arch.

Step 4

Select which block to work with first. Fold the quarter circle in half, aligning the straight cut edges and press a crease in the “center” of the arc using a wooden seam roller, your finger, a chop stick, or a tool of your choice.

Note that I started with 5-inch squares of fabric, so a single reference is sufficient. If you are working with larger starting sizes, it is likely beneficial to then fold each straight edge over to meet your center crease to create (2) additional quarter arc creases.

Step 5

Fold the arch fabric in half, aligning the square corners and press a crease in the “center” of the arch using a wooden seam roller, your finger, a chop stick, or a tool of your choice.

Note that I started with 5-inch squares of fabric, so a single reference is sufficient. If you are working with larger starting sizes, it is likely beneficial to then fold each straight edge over to meet your center crease to create (2) additional quarter arc creases.

Step 6

Placing right sides together, align the edges of the quarter circle arc and the arch at the creased center marks and pin the fabric together.

If you created additional creases, pin them together in a similar fashion at this time.

Step 7

Working from the center out, gently curve the arch fabric around the quarter circle and pin the fabric together halfway to the edge of the quarter circle and at the edge of the quarter circle.

Adjust the number of pins and placement as necessary for the size block you are working with.

Step 8

Repeat pinning process on the other side or continue until the two pieces are fully pinned together.

I am showing the back side of the pinning process to emphasize that the arch fabric will extend beyond the edge of the quarter circle. This is the way it is supposed to be; do not try to force the edges to meet. Because we started with the same sizes of fabric when we made the initial cut, the arch will be larger than the cut quarter circle when piecing.

Step 9

With the arch fabric on top, begin sewing the pieces together using a 1/4-inch seam allowance. I like to remove the pins when my presser foot is in this relationship to the first pin and then I use the pin like a stiletto to help encourage the arch fabric to stay in the correct position over the quarter circle fabric until I come to the next pin. I tend to sew 2 to 3 stitches and then adjust. When I adjust, I make sure the sewing machine needle is down, and then I lift the presser foot and gently rotate the block to maintain the 1/4-inch seam allowance.

Step 10

Continue on in this fashion around the entire perimeter of the quarter circle arc.

Note that you can see there is a “fold” in the arch fabric just in front of the presser foot in this photograph. As I approach these natural waves in the fabric, I stop with the sewing machine needle down and lift the presser foot so that I can then lift the left hand side edge of the arch fabric up and encourage the fold to move away from me and under the presser foot. This allows the fabric in front of the presser foot to lay flat again and helps decrease the number of tucks I sew. Again, this is a stronger challenge for smaller curves. If you start with larger curved piecing this will be less of a challenge or issue.

Step 11

This is what the unit will look like when you are done sewing them together. I like to use my wooden seam roller to then gentle press the arch fabric down, effectively pressing the seam toward the arch / away from the quarter circle. Press.

Step 12

This is the view of the back of the pieced block after it has been pressed. Note that the center creases are aligned and that the arch fabric extends beyond the quarter circle.

Step 13

The final step is to trim your block to its unfinished size! I suggest trimming blocks 1-inch smaller than the size you started with:

If you started with 5-inch squares, trim to 4-inch square (3 1/2-inch square finished)

If you started with 8 1/2-inch squares, trim to 7 1/2-inch square (7-inch square finished)

If you started with 10-inch squares, trim to 9-inch square (8 1/2-inch square finished) (etc.)

Because these are improv cut circles, you may find that you cannot trim to have 1/4-inch of the arch material at the edge of the block: you will likely have more or less than that amount. That is the fun of improv and I like to embrace each block being trimmed slightly differently.

In looking at your Comes in Waves I didn’t realize that those blocks were improv pieced. Very well done! I admit that I still tend to shy away from curved piecing but this is very doable and who can resist using that wooden seam roller!

That’s for sharing. Good tip about the arc extending past the main piece — I would have tried to line up the edges. I might give this a try. We learned curved piecing from Violet Craft at Glamp Stitchalot last year.

I’m so itching for a piecing project right now! This totally reminded me of the Meadow quilt curves, maybe I should work on that next. Have you tried the no-pin method for curves? (there’s a 2 minute youtube video) I’ve tried both methods and really like the no-pins method!

About Yvonne

Yvonne @Quilting Jetgirl Quilter | Designer | Tech Editor | Blogger

Yvonne is a former aerospace engineer turned modern quilter, designer, and technical editor. She was introduced to quilting by her paternal grandmother in high school when her grandmother offered to hand quilt a twin-size quilt to use in her college dorm room if Yvonne made the quilt top. Now, 25 years later, Yvonne has developed a style that bridges her technical background and love of bold color, specializing in transparency color play and bold, geometric designs. Yvonne’s quilts have been featured in numerous national and international magazines, quilt shows, and Modern Quilts: Designs of the New Century. She lives in Tehachapi, California, with her husband.